You can't know if yo are a good or bad copywriter easily. Because you have to wait till you see if sales for washing machines, pizzas and hand sanitizers went up after your copy was published.

Now you can change that, and become a better copywriter everyday.

Since twitter let's you publish 140 character messages including links, it's a great way to train as a copywriter. Because if you write good convincing copy, then people will click on your link and sacrifice their time to check out what you shared.